Hydroforming is used to create parts because of its ability to integrally form a hollow tube, beam, or other member with a complex shape that would otherwise have to be fabricated from several pieces and/or bent into shape. A thin-walled blank is inserted into a die cavity that closely matches the exterior of the part to be created. Then the tube is pressurized with a hydraulic fluid to expand it into the shape of the die cavity. If further processes are required, the completed part is depressurized and removed.
Hydroforming allows complex shapes with concavities to be formed, which would be difficult or impossible with standard solid die stamping. Hydroformed parts can often be made with a higher stiffness to weight ratio and at a lower per unit cost than traditional stamped or stamped and welded parts.
Often, various holes or openings may be desired in the wall of the final part. These may be drilled or cut after the fact, but it may also be desired to incorporate the hole piercing process into the hydroforming process itself. Incorporation of the hole piercing process is beneficial to reduce the total number of steps in the manufacture of the part, and may have other benefits such as: reduced failure rates, reduced scrap material, tighter tolerances, et cetera.